How to Make Wood Joints

A butt joint is the easiest of all simple wood joints, but also is the weakest. The cut end of one board butts up against the edge of another piece at a right angle.

The key to every type of wood joint is having smooth, square cuts on the boards, and the butt joint is no exception. This basic joint is glued but can be reinforced using screws or nails fastened through the face of one board and into the end grain of the other board.

Doweling is another method of adding some rigidity to a basic butt joint. Two or more short dowels are inserted and glued into corresponding holes in adjoining boards. A dowel jig can be used to ensure the holes are aligned correctly.

A variation of the butt joint is the mitered butt joint, where the ends of the adjoining boards are cut at 45-degree angles for a cleaner look. The advantage to this is only aesthetic. No end grain is shown, but the mitered corners provide no additional strength.

A pocket joint is a type of wood joinery where a slot is pre-drilled at an angle to provide a pilot hole for a screw to connect two boards. The fasteners are less obvious on the finished product. They also create a stronger joint than those screwed into face on one side of a butt joint. Pocket hole joints are often found in cabinets and furniture where strength is essential.

A pocket hole jig is usually used for this type of wood joint because accuracy is crucial for the pre-drilling. A special bit with a pilot tip is attached to a power drill and inserted into the angled hole in the jig. A depth-stop collar on the bit prevents drilling to deeply. With the board secured, pre-drilling bores a hole wide enough for the head of the screw to be concealed and the pilot hole aimed accurately at the adjoining piece.

A dado is a flat-bottomed recess cut across the grain of a board. A piece of wood the same thickness as the width of the dado fits snugly into the slot to make the joint. A typical application might be for a bookcase or cabinet. A dado is cut into the upright pieces of wood and the stock for a shelf slides into it.

This type of wood joint can be made using a table saw equipped with a stacked dado saw blade set. It consists of two blades with chippers placed in between. The width of a dado depends on the number of chippers stacked between the blades.

Another method for making a dado uses a router fitted with a straight cutting bit.

No matter how the dado or groove is cut, its depth should be at least one-third of the board’s thickness and no more than half.

Note: While a dado goes across the wood grain, a “groove” runs with the grain and is cut using similar techniques.

A rebated joint is commonly called a rabbet. It's is essentially a dado that is cut into the edge of a board. Unlike the three-sided channel of a dado, a rabbet is an L-shaped notch that accommodates another board.

Rabbets can be used for a number of projects to make one surface of the joint flush with another. A rebated joint can receive paneling for the back of a cabinet or the bottoms of drawers and boxes.

Rabbets are made using techniques similar to those for making dados. Using table saws or routers produce good results.

Mortise and tenon joints are a classic method of wood joinery known for both strength and elegance. A peg, or tenon, is cut into the end of one board to fit snugly into a hole, or mortise, on the adjoining piece of stock for a strong joint. Precise marking and cutting are crucial to mortise and tenon joints because tight fits lead to superior strength.

Historically, woodworkers hand cut mortises and tenons using chisels and a mallet. Today, power tools can reduce the amount of time necessary to complete the work. Cut the mortise first and then form the tenon, whether you use traditional techniques or modern methods.

Many woodworkers today use a mortiser to create the hole for a tenon. A mortiser is specialty drill press that uses a bit encased by a four-sided chisel. Some mortising drill bits or mortising kits can be used with a standard drill press, which broadens the versatility of that workshop tool.

For tenons, a band saw can be used to shape the peg by cutting away waste around it. A homemade tenoning jig can also help make cuts to the end of a board placed vertically on a table saw.

A mortise and tenon jig used with a plunge router makes cutting both elements of the joint easier, especially when numerous duplicate cuts are needed.

A bridle joint can be considered a cousin to mortise-and-tenon. It makes a strong and attractive wood corner joint for frames. The tenon is one-third of the board’s thickness. It slips into the mortise made at the end of a second board to form the rigid corner of a frame.

On a table saw, use a dado blade with the cut height set to the width of the stock. With the board positioned vertically and centered in a jig, make the cut to create the slot. Then trim the outside edges of the tenon piece so it mates with the tenon for the bridle joint.

Biscuit joinery is a popular method used to join multiple boards together for a tabletop or to join face frames and cabinet boxes.

A biscuit joiner is a specialty tool similar to a router. It's used to cut thin slots into corresponding stock. A wooden oval plate, known as a biscuit or wafer, is inserted and glued into the slots to hold the pieces together.

A half-lap wood joint is made by cutting away half of the thickness of two pieces of the same dimension. It allows them to overlap and form a right angle without adding additional height or act as a splice to extend length.

Lap joints are often used when building the framework of furniture such as dressers or desks with drawers.

A table saw can be used with a stacked dado blade set to make a lap joint. It can be in the middle of a piece of stock or at the end of a board for a corner joint. Use scrap pieces as you adjust the saw to get the blade depth set accurately. Once that is done, repeated cuts for mating surfaces can be made with ease.

The dovetail joint is a traditional hallmark of wood corner joints. Tails and pins are cut into stock at an angle to interlock, creating a joint that is just as attractive as it is strong. This type of wood corner joint is commonly found in drawer construction.

Hand-cutting dovetails can be a tricky task, but using dovetailing jig and a router with the proper bit can produce beautiful results with only a little practice. Cut the tails of the joint first and then cut the pins.

A box joint is a simplified version of dovetails. It provides ample surface area for wood glue to make a very sturdy joint. Tails and pins are cut square on the end of stock just as deep as the stock’s thickness. They interlock with the corresponding cuts on another board.

Use a table saw and a dado blade to form the fingers. A box joint jig and router with a square bit makes quick work of the recesses needed for solid construction of jewelry boxes or drawers.